Ship mooring arrangement and a submerged oil storage tank

ABSTRACT

A ship mooring arrangement comprising a movable fender system capable of varying the spring constant optionally by selecting the dimensions and shapes of a fender mechanism and a ballast tank type of weight, said weight is so constructed to be filled with water and to be sunk, a storage tank fixed at the sea bottom by means of the anchoring piles, a main frame secured to the foot of said oil storage tank by fixing rigidly the posts of said frame to said anchoring piles.

United States Patent 11 1 Arita et a1. 1 1 Jan. 30, 1973 [5 SHIP MOORING ARRANGEMENT AND FOREIGN PATENTS-OR APPLICATIONS A SUBMERGED OIL STORAGE TANK 796,440 6/1958 Great Britain 1 1.61/48 [75] Inventors: Yukio Arita; Katsuya Ninomiya, 636,643 2/1962 Canada ..114/219 both of Hiroshima, Japan [73] Assignee: ilitsilibisiii k J1-1Ikogy0 Kabushiki Primary Examiner Trygve M Bhx ms 0 apan Att0rneyCushman, Darby & Cushman [22] Filed: Feb. 25, 1971 [21] Appl. No.: 118,921

[57] ABSTRACT [30] Foreign Application Priority Data A ship mooring arrangement comprising a movable March 5, 1970 Japan ..45/18304 fender System capable of varying the Spring Constant optionally by selecting the dimensions and shapes of a 52 US. Cl. ..114/230, 61/48, 114/219 fender mechanism and a ballast tank yp of g [51] Int. Cl ..B63b 21/04, B63b 21/00 said igh i so constructed o e fi le wi h water [58] Field of Search ..1 14/219, 230, 0.5 T; 9/8 P; n to be n storage k fixed at th see om 61/48, 46 by means of the anchoring piles, a main frame secured to the foot of said oil storage tank by fixing rigidly the [56] References Cited posts of said frame to said anchoring piles.

UNITED STATES PATENTS 2 Claims, 6 Drawing Figures 3,360,810 1/1968 Busking ..9/8 P 2,039,151 4/1936 Dubois ..114/219 PALENTEBJM 30 1915 FIG. I

FIG.2

YUKIO ARITA KATSUYA NINOMIYA ATTOIN EYS SHIP MOORING ARRANGEMENT AND A SUBMERGEI) OIL STORAGE TANK This invention relates to a ship mooring arrangement which is very effective for use in gathering, storing and loading oil.

In general, the oil excavated from an undersea oil field is fed from a flow station through a gathering station and a submarine pipe to a land oil storage tank, and the oil is shipped again through the submarine pipe to a mooring arrangementin the offing. In case of oil field far from a land, a long submarine pipe is necessary, and yet huge facilities for feeding oil to the tank on land is also required. A mooring arrangement must be provided far from the land, since a modern tanker requires large depth of the sea as its structure becomes enlarged, and accordingly expensive construction cost is incurred. As a result, it is desirable to decrease the construction expense by providing a facility which has functions of gathering, storing and loading oil in the oil field district.

There exist two types of the conventional ship mooring arrangements as general of dolphin, one of which is constructed by erecting a deck after oblique or vertical piles are hammered, and the other ofwhich is towed to the objective place and is fixed on the bottom of the sea by piles after frames are manufactured inthe factory. In this case, both types have a great deal of rigidity in the frame, so it is so constructed that the contacting energy of the ship to the shore is absorbed by the deformation of a rubber fender provided in the dolphin. However, since the deforming amount of the rubber fender is at most 45 cm and it has large spring constant, the contacting shock force becomes great, and accordingly the mooring arrangement must be enlarged. For this reason, it is necessary to intend to lighten the mooring arrangement by adopting a mechanism which may absorb greatly the contacting energy.

This invention contemplates to provide a ship mooring arrangement which may sufficiently satisfy the aforementioned necessity, and the scope of this invention resides in a ship mooring arrangement which adopts a movable fender system capable of selecting any spring constant by selecting dimensions and shapes of both fender mechanism, and weight, and fixes the main frame of mooring arrangementto the foot of the oil storage tank in such a way that the posts of the main frame are fixed rigidly to the anchoring piles of the tank and which also adopts the ballast tank type of weight of the fender system to be filled with water to be sunk onto the top of the tank. Thus, the present invention may lighten the weight of facility and may also reduce the construction expense.

The present invention will now be described in detail with reference to one embodiment shown in the attached drawings.

In the attached drawings, FIG. 1 is a plan view of a ship mooring arrangement according to the present invention, FIGS. 2 through 5 are sectional views of the arrangement taken along the lines and arrows A,B,C and D, respectively in FIG. 1, FIG. 6 is an analytical view of a fender system in accordance with this invention.

In FIG. 1, reference numeral 1 illustrates a submarine oil storage tank, 2 a ship mooring arrangement, 3 a platform for accomodatinga facility for loading and unloading oil to or from a moored ship 4. If the oil is supplied directly to the oil storage tank 1 from a flow station as in they case of oil field districts, a gas separating plant (not shown) is provided on the platform 3. In FIG. 2, which shows the section of the submarine oil storage tank 1, reference numeral 10 designates an outer shell of the tank having proper curvature, 1b and 10 supporting frames of the outer shell 1a, 1d beams provided on a bottom plate, 1e foot of the tank filling concrete, 1 f piles for anchoring the tank on the sea bottom and numerals lg and 1h designate respectively openings for flowing in and out seawater into and from the tank and these are provided on the supporting frames 1b.

In FIGS. 3 and 4, which show the section of the ship mooring arrangement 2, reference numeral 2a depicts main frames of the ship mooring arrangement fixed to the foot 1e of the oil storage tank 1, 2b a movable fender frame, 20 a pivot pin for mounting the fender frame rotatably onto the main frame 2a of the mooring arrangement, 2d a fender, 2e weights of ballast type for absorbing the energy caused in case of mooring the ship for. In FIG. 5, which shows the section of the platform'3 for loading and unloading the oil, 3a a platform for loading various facilities for loading and unloading the oil and various devices and equipment for separating gas if required, and 3b designates posts of the platform of which inner hollow portions serve as oil passages, and 3c is an opening for introducing the oil in the storage tank 1 to said oil passage.

In thus constructed arrangement, the submarine oil storage tank 1 has spherical outer shell 1a of the tank as shown in FIG. 2 to form an economical structure againstthe inner pressure produced when oil is filled within'the tank, and the tank of a huge capacity has plural spherical outer shells to make the structure economic and convex outer shell la to reduce the quantity of the mixed layer of seawater and oil when the residual oil is slight, and the tank itself is constructed in a spherical shape by the outer shell 1a of the tank, supporting frames 1b and 1c, and beams 1d of the bottom plate so as to provide an economic construction for the inner pressure and wave pressure. Thesupporting frame 1b is so constructed as to be in closed section of water-tight type, and an opening lg opened outwardly is provided at the upper portion of the supporting frame and an opening 1h opened in the tank 1 is provided at the lower portion of the supporting frame, whereby as oil is introduced into the tank or is fed out of the tank, the seawater within the tank is optionally discharged from the tank or is flown into the tank, thus, the buoyancy of the tank is reduced. And, concrete is filled into the foot 1e of the tank in order to prevent the tank from floating due to the buoyancy produced as oil is filled into the tank and floating pressure caused by the wave, and to also prevent the tank from sliding due to the horizontal force produced by the tide.

As shown in FIGS. 3 and 4, in the ship mooring arrangement 2 a main frame thereof 2a is fixed to the foot 1e of the oil storage tank 1 and the posts of the main frame are rigidly fixed to the piles If by filling concrete therebetween so that the shocking force of the ship upon mooring is transmitted directly to the bottom ground of the sea. A movable fender system comprises a fender system 2b, a pivot pin 20, a fender 2d and a weight 2e. Said fender system 2b rotates around said pivot pin 20 so as to greatly decrease the shocking force of the ship upon mooring.

Though the conventional mooring facility absorbs the contacting energy of the ship to the shore only by rubber fender, the present movable fender system may absorb the contacting energy of the ship to the shore by the buoyancy of the weight 2e and displaced amount thereof by rotating the fender mechanism 2b around the rotary pin 20 as a center when the contacting energy of the ship to the shore is applied tothe system.

In comparison of the conventional fender system with the present system as to the absorbing amount of the contacting energy of the ship to the shore, the following formulas are derived from the drawing in FIG. 6:

The conventional fender system: E= I k x dx The novel fender system: E= f k x,dx f k x dx E: absorbing energy k k spring constant x x displacing amount As shown in the above formulas, the energy absorbed by the novel fender system increases greatly by the rotation of the fender mechanism and the spring constant of the fender mechanism may be selected op tionally depending upon the dimensions and shapes of the fender system and weight.

The weight 2e is constructed as a type of a ballast tank, and so the external force to be applied to the rotary pin 20 and main mechanism 2a in case of stormy weather, can be decreased by pouring water into'the tank so that the latter be sunk onto the base 2h.

Further, the example of the application of this invention will further be described. In the oil field district, the oil produced from the well in the oil field is fed through the flow station to the gathering and loading platform by the sea bottom pipe, after gas is separated therefrom, it is stored in the oil storage tank, and the oil may be shipped by approaching the tanker to the shore, with the result that the arrangement of this invention may be utilized as a facility having general functions of gathering, storing and shipping the oil.

From the foregoing description it will be obvious that the mooring arrangement can be utilized independently of the oil storage tank facility and, conversely, the submerged oil storage tank can be used, if desired without the mooring frame construction.

What is claimed is:

1. A ship mooring arrangement comprising a submerged elongated storage tank having a flat bottom anchored to the sea bottom and generally convexly curved exterior walls, said tank having a top provided with at least one generally planar platform, a main frame having a base connected to said tank and anchored in the sea bottom, said main frame extending upwardly above the sea surface a predetermined distance above said platform, said arrangement further including at least one adjustable fender comprising a support frame pivotally mounted about a generally horizontal pivot axis on said main frame adjacent said planar platform of said storage tank, said support frame having a ship engaging member attached thereto on one side of said pivot axis, located outside of said main frame, and a ballast tank attached on the opposite side of said ivot axis and located inside of said main frame substan rally directly above said planar platform and spaced therefrom a predetermined distance, said ballast tank being adapted to be filled with a liquid to ad-.

just its buoyancy, said ballast tank having a liquid holding capacity and said support frame having dimensions so that said ballast tank can be sunk to come in contact with said planar platform.

2. The arrangement as claimed in claim 1 wherein said storage tank has an upper and a lower side and at least one opening in each of said sides so that when oil is fed to or from said storage tank through one of said openings, sea water will pass out of or into, respectively, said storage tank through the other of said openings in proportion to the oil displaced. 

1. A ship mooring arrangement comprising a submerged elongated storage tank having a flat bottom anchored to the sea bottom and generally convexly curved exterior walls, said tank having a top provided with at least one generally planar platform, a main frame having a base connected to said tank and anchored in the sea bottom, said main frame extending upwardly above the sea surface a predetermined distance above said platform, said arrangement further including at least one adjustable fender comprising a support frame pivotally mounted about a generally horizontal pivot axis on said main frame adjacent said planar platform of said storage tank, said support frame having a ship engaging member attached thereto on one side of said pivot axis, located outside of said main frame, and a ballast tank attached on the opposite side of said pivot axis and located inside of said main frame substantially directly above said planar platform and spaced therefrom a predetermined distance, said ballast tank being adapted to be filled with a liquid to adjust its buoyancy, said ballast tank having a liquid holding capacity and said support frame having dimensions so that said ballast tank can be sunk to come in contact with said planar platform.
 1. A ship mooring arrangement comprising a submerged elongated storage tank having a flat bottom anchored to the sea bottom and generally convexly curved exterior walls, said tank having a top provided with at least one generally planar platform, a main frame having a base connected to said tank and anchored in the sea bottom, said main frame extending upwardly above the sea surface a predetermined distance above said platform, said arrangement further including at least one adjustable fender comprising a support frame pivotally mounted about a generally horizontal pivot axis on said main frame adjacent said planar platform of said storage tank, said support frame having a ship engaging member attached thereto on one side of said pivot axis, located outside of said main frame, and a ballast tank attached on the opposite side of said pivot axis and located inside of said main frame substantially directly above said planar platform and spaced therefrom a predetermined distance, said ballast tank being adapted to be filled with a liquid to adjust its buoyancy, said ballast tank having a liquid holding capacity and said support frame having dimensions so that said ballast tank can be sunk to come in contact with said planar platform. 